Hanger bars for electric outlet boxes



Feb. 16, 1960 R. D. cooK ET AL 2,925,236

HANGER BARS FOR ELECTRIC OUTLET BoxEs Filed Dec. 24, 1957 INVENTORS.Raymond VD. Cook William A. Lang THEIR A TTORNEYS United States Patent O2,925,236 HANGER BARS FOR ELECTRIC OUTLET BOXES Raymond D. Cook andWilliam A. Lang, Pittsburgh, Pa., assignors to Steel `City ElectricCompany, Pittsburgh, Pa., a corporation of Pennsylvania ApplicationDecember 24, 1957, Serial No. 705,025 Y 4 Claims. (Cl. 248-276) Thisinvention relates to hanger bars for electric outlet boxes, moreparticularly to an improved device for attaching `the outlet box to thehanger bar. t

Due to the increasing cost of building construction any device whichsimplifies existing installation procedures, thereby reducing laborcosts, is a very valuable advance. Our invention accomplishes thisresult, providing a hanger` bar which is easy to construct and simple toinstall. The prior art shows hanger bars which are diicult to" assemble,requiring a workman to make several adjustments and alignments. Ourinvention eliminates most ofthis diiculty. It discloses a hanger bar towhich an outlet box can be attached by simply tightening one screw. Theconstruction of the attaching mechanism automatically aligns this screwwith its bore and directs the screw to the bore. v,

We have shown a preferred embodiment of our invention in theaccompanying drawings, in which:

Figure 1 is front elevation of a positioned hanger bar embodying ourinvention with an outlet box attached thereto;` t

Figure 2 is a transverse section of the hanger bar on line II-II ofFigure l;

Figure 3 is a partial longitudinal section of the hanger bar on lineIII-III of Figure 2;

Figure 4 is a perspective view of a box carrier, with guide prongsextending therefrom, adapted to tit in a hollow center portion of thehanger bar; and

Figures 5 and 6 are perspective views of two forms of box fasteners forholding an outlet box to the hanger bar.

More particularly, a hanger bar embodying our improved attaching devicecomprises a pair of hollow elongated telescopic members 1 equipped attheir opposed ends with plates 2 for securing the members to oor joists3 likewise the plates may be secured to wall studs. While telescopicmembers of rectangular cross section are easier to fabricate and areshown in the drawings, any suitable cross section may be used.

Each of the telescopic members are longitudinally slotted along oneface. ln a bar having a rectangular cross section these slots may beformed by turning toward each other the edges of a sheet of metalpreviously bent to form two sides perpendicular to the bottom. When themembers are assembled the slots are aligned, thereby providing anopening 4 into the hollow center section of the members. In order thatan outlet box may be located at any position between oor joists theopening will generally extend throughout the length of the telescopicmembers.

A box carrier 5 is inserted in the hollow telescopic members andretained therein by shoulders 6 formed by the opposed sides of themembers adjacent the opening 4. By constructing the box carrier nearlyas Wide as the hollow center portion of the members and slightly longerthan that dimension, sidewise turning of the box carrier is prevented;thus while the box carrier is free to move lengthwise in the members, itwill not move side- ICC I wise or turn when a locking screw 12 in :a boxfastener 13 is inserted in a bore 11 in the box carrier.

Guide prongs 7 extend from the box carrier through" the opening 4 in themembers. These guidev prongs are spaced so as to automatically centertheoutlet box 8 when it is attached to the bar through a hole 9 in one sideof the box, which holeis slightly larger indiameter than the distancebetween the outer surfaces of the guide prongs. The opposed faces 10 ofthe guide prongs are sloped inwardly toward the center of the boxcarrier andA the bore 11 provided in the box carrier. By this means thelocking screw 12 is directed to the bore by the guide prongs.

The box fastener 13 carrying the screw 12 has a rectangular cavity 14which is adapted to it over the guide prongs. The cavity is constructedjust slightly longer than the distance between the outer surfaces of theguide prongs. Thus when the box fastener is pla'ced over the guideprongs it takes a position with respect to the box carrier whichautomatically aligns the locking screw 12 with the bore 11 in the boxcarrier. cavity is just slightly greater than the width of the guideprongs thereby preventing turning of the box fastener when the lockingscrew is being engaged. The outer periphery 15 of the box fastenerextends over the periphery of the opening 9 in the outlet box andthereby holds the outlet box firmly between the box fastener and thehanger bar when the locking screw is fastened.

The locking screw 12 extends through a bore in the box fastener, whichbore is threaded with half threads so as to keep the screw and the boxfastener together when they are not secured to the box carrier. Theupper portion of-the shank 17 of the locking screw 12 is smooth, only asmall portion of the end being threaded. By this means the screw may beslipped into engagement with the bore 11 in the box carrier withoutrequiring turning until contact is made with that bore.

Figures 5 and 6 show two different types of box fasteners which may beused. The box fastener shown in Figure 5 is provided with an externallythreaded stud 16 extending therefrom.

It will be seen that our invention makes the installation of outletboxes much easier than has heretofore been possible. The outlet box isplaced over the guide prongs extending from the opening in the bar; thebox fastener is placed over the guide prongs, automatically centeringthe bores in the box carrier and the box fastener. In certain instances,there may be such clearance between the smooth portion of the shank 17and the bore in the box fastener that the screw can pivot in the bore.In such instances, the sloping sides of the guide prongs will guide thescrew into engagement with the bore in the box carrier. Then thetelescoping members are attached to the joistsand the box carrier movedinto the desired position. The outlet box is firmly held by tighteningthe screw.

While we have described a present preferred embodiment of our invention,it is to be understood that it may be otherwise embodied within thescope of the appended claims.

We claim:

l. In a hanger bar for electric outlet boxes, said bar having a pair ofhollow elongated telescopic members equipped at their opposed ends withmeans for securing the members to building joists or studs, improvedmeans for securing an outlet box to the bar, said means comprising anelongated slot in each member said slots being aligned with each otherso as to provide an elongated opening into the interior of the members,shoulders formed by the opposed sides of said opening, a box carrieradapted to fit in said members and retained therein by said shoulders,guide prongs extending from the box Patented Feb. 16, 1960 The width ofthe` carrier tlir'ug'li s''d opening and adapted to extend through" anVopening in the outlet box, a box fastener adapted to fit over said guideprongs and the periphery oftheopenins inthe boxandthereby hold the boxrmlyv between said 'embers Aand said box fastener, and means to securethe box fastenermto'mthe boxrcarrier.V

'2 Ina hanger blarfor electric outlet boxes, said bar havV g a pairofhollow elongated telescopic members equippedaftjtheir opposed endswith means for securing theA members to building joists orstuds,'improved means for securing'` an outletbox to the bar, said meanscom# prising an `elon''gamteds'lot in each member said slots beingalignedfwit'hfeach other so as to provide an elongated o" ng .into theVinterior ofthe members, shoulders forme y theroppos'ed sides of saidopening, a box carreradapted toiit in said members and retained thereinby said shoulders, guide prongs extending from the box carrier ,throughsaid openingrand adapted toextend throughr an opening in the outlet box, a box fastener adahtedjtoft over said guide prongs and the peripheryofthe opening in said boxV and thereby hold the box firmly` between saidmembers and said box fastener, an externally threaded `stud extendingfrom said box fastener for: supporting fixtures and means to secure thebox fastener tothe box carrier.

In ahanger bar ,for electric outlet boxes, said bar having a pair ofhollow elongated telescopic members equipped attheir opposed ends withmeans for securing the members to building joists or studs, improvedmeans for seciirinfg anV outlet box to the bar, said means comprising anelongated slotin each member said slots being aligned with each other soas to provide an elongated opening'into the ,interior of the members,shoulders fiornedby the opposed sides of said opening, a box carrieradapted to 'tin'saidhme'mbers' and retained therein bygsaid Shouldersand having a centrally positioned e'aded bore,V guide prongs extendingfrom thel box rter through saidv opening and adapted to extend ofughinOPi-vl'ng'in the outlet box,y aAbox fastener havig acavty adapted to fitover said guide prongs and said "spaanse s f" ,a I

centrally positioned threaded bore, said box fastener being ofA suicientsize to extend overk the periphery of the equipped at their opposed endswith means `for Securing the members to building joists or studs,improved means for securing an outlet box to the bar, saidv meanscomprising an elongated slotin each member said slots being aligned witheach other so as to provide an elongated opening into the interior ofthe members, shoulders formed by the opposed sides of said opening, abox carrier adapted V,tor fit infsaid members ,and retained `therein byVsaid shouldersV andV having va. threaded bore, guide prongs extendingfrom the box carrier Vthrough said openfv ing and adapted to extendthrough an opening Vin ythe ontletV box, the opposed vfaces of saidguide prongs. being angled tovvard the bore in the box carrier, a boxfastener provided with a bore adapted tofit over saidy guide prongs andthe periphery ofthe 'opening in the box andtlereby hold the box firmlybetweensaid members and said box fastener, and a screw adaptedv toengage said bores to se'f cure the box fastener to the box carrier, saidscrew being directed toward the bore in the box carrier by the angledfaces of the guide prongs.

References Cited in the file of this patent UNITED STATES PATENTS

